Advertisements
Advertisements
प्रश्न
For a certain reaction ΔH0 is −224 kJ and ΔS0 is −153 J K−1. At what temperature the change over from spontaneous to non-spontaneous will occur?
Advertisements
उत्तर
Given:
ΔH0 = −224 kJ,
ΔS0 = −153 kJ K−1 = −0.153 kJ K−1
To find: T = ?
Formula:
∴ `ΔS^0 = (ΔH^0)/T`
∴ T = `-(ΔH^0)/(ΔS^0)`
= `- (-224 kJ)/(-0.153 kJ k^-1)`
∴ T = + 1464 K
Since ΔH0 and ΔS0 are both negative, the reaction is spontaneous at low temperature. A change over will occur at 1464 K. The reaction is spontaneous below 1464 K.
APPEARS IN
संबंधित प्रश्न
Answer the following in one or two sentences.
State whether ΔS is positive, negative or zero for the reaction 2H(g) → H2(g). Explain.
Answer the following in one or two sentences.
State second law of thermodynamics in terms of entropy.
Answer the following question.
Although ΔS for the formation of two moles of water from H2 and O2 is –327J K–1, it is spontaneous. Explain.
(Given ΔH for the reaction is –572 kJ).
For a certain reaction ΔH° = 219 kJ and ΔS° = –21 J/K. Determine whether the reaction is spontaneous or nonspontaneous.
Answer the following question.
Determine whether the following reaction is spontaneous under standard state conditions.
2H2O(l) + O2(g) → 2H2O2(l)
if ΔH° = 196 kJ, ΔS° = –126 J/K, does it have a cross-over temperature?
Equilibrium constant for a reaction is 20. What is the value of ΔG° at 300 K? (R = 8 x 10-3 kJ)
A system is changed from an initial state to a final state by a manner such that ∆H = Q. If the change from initial state to final state was made by a different path, then ____________.
Identify the INCORRECT statement.
In how many of the following, ∆S is positive?
i. Melting of ice
ii. Sublimation of iodine
iii. Dissolution of CuSO4 in water
iv. Condensation of water vapour
v. Dissociation of H2 molecule into atoms
vi. Conversion of carbon dioxide gas to dry ice
vii. Vaporization of acetone
Which one of the following has ΔS0 greater than zero?
For the following reaction:
\[\ce{Fe2O3_{(s)} + 3CO_{(g)} -> 2Fe_{(s)} + 3CO2_{(g)}}\]; ΔH0 = −29.8 kJ and ΔS0 = 15 J K−1. What is the value of \[\ce{ΔS_{(total)}}\] at 298 K?
Heat of combustion of C(s), H2(g) and C2H6(g) are −x1, −x2 and −x3 respectively. Hence heat of formation of C2H6(g) is ____________.
Calculate the amount of heat liberated during formation of 2. 7 kg of water if heat of formation of water is - 284.5 kJ mol-1.
The H-H bond energy is 430 kJ mol-1 and Cl-Cl bond energy is 240 kJ mol-1. ΔfH for HCl is - 90 kJ, then H-Cl bond energy is ______.
The equilibrium constant for a reaction is 10, value of ΔG° at 300 K is (R = 8 × 10-3 kJ)
For a reaction ΔH = - 30kJ and ΔS = - 45 JK-1, at what temperature reaction changes from spontaneous to non-spontaneous?
For which of the following reaction, ΔH = ΔU?
When will be change in Gibb's free energy always negative?
In which of the following reaction the value of Kp will be equal to Kc?
Dinitrogen and dioxygen combined to form nitrous oxide in equilibrium at 850 K. The equilibrium constant for this reaction is 0.56. If the equilibrium concentration of nitrous oxide gas is 3 × 10-3 M and both dinitrogen and dioxygen have the same concentration, then what will be the concentration of dinitrogen gas in M?
What is a spontaneous process? What are its characteristics?
Calculate ΔG for ΔH = − 110 kJ, ΔS = + 40 J K−1 at 400 K.
Find out the value of equilibrium constant for the following reaction at 298 K, \[\ce{2NH3_{(g)} + CO2_{(g)} ⇌ NH2 - COONH2_{(aq)} + H2O_{(l)}}\] Gibbs Standard energy change 298 K = –13.6 kJ mol−1.
Define second law of thermodynamics.
Which of the following is true about the decomposition of ozone?
The entropy of vaporisation of benzene is 85 J K−1 mol−1. When 117 g of benzene vaporises at its boiling point, what is the entropy change of the surroundings if the process is at equilibrium?
